Theoretical Analysis And Finite Element Study Of Bolted Joints With Slotted-in Steel Plate In Glued Laminated Timber

The wooden structure is a traditional Chinese architectural structure system with a profound cultural heritage.The traditional wooden structure generally uses the tenon-mortise connection.In recent years,modern wood structure has been vigorously promoted in China,and has developed rapidly in the direction of assembly and multi-story buildings.In the modern wood structure building system,the bolted joints with slotted-in steel plate is widely used because of its easy installation and construction,clear stress,and beautiful effect.Bolt-steel joints are commonly used in glulam structures.GB50005-2017 is not perfect for the calculation method of bolt-steel joints.At the same time,the standard does not provide for the stiffness and bending moment-angle model of the joint.Therefore,the existing regulations of "Wood Structure Design Standard" GB50005-2017 are not enough to support the overall force analysis and joint design of glulam structure.The performance of the joint is the key factor that determines the overall performance of the wooden structure.Therefore,it is of great significance to improve the theoretical calculation model and design method of the the bolted joints with slotted-in steel plate.In response to the above problems,in order to accumulate relevant knowledge in the theoretical calculation method of bolted joints with slotted-in steel plate,this paper has carried out research work in the following aspects:(1)Relevant to the wood structure design standards in four regions of China,the United States,Europe and Canada The calculation method and corresponding advantages and disadvantages of the wood structure bolt connection are summarized;(2)Based on the four yield modes of bolt double shear,based on the ideal rigid-plastic model,a bolt-steel plug suitable for Chinese codes is derived Calculation method of plate node bearing capacity and theoretical model of node bending moment-turn angle,and reference to the existing test data to verify its rationality;(3)3 groups of 9 bolt-steel bolted joints with slotted-in steel plate were designed,using the calculation method proposed in this paper Parametric analysis of its performance was conducted,mainly considering changes in parameters such as section size,bolt diameter,and bolt arrangement;(4)ABAQUS was used to perform finite element simulation on 9 bolted joints with slotted-in steel plate.Through the above work,the following conclusions are obtained:(1)According to the relevant regulations on bolt joint calculation in the Chinese,American,European,and Canadian specifications,when the diameter of the bolt and the angle between the load and the wood grain direction are increased,the bearing capacity of the bolt pin groove is reduced to varying degrees,increasing the density of the wood,The bearing capacity of bolt pin groove is improved.(2)According to the relevant regulations on bolt joint calculation in the Chinese,American,European,and Canadian specifications,as the diameter of the bolt,the thickness of the wood side material and the density of the wood increase,the shear bearing capacity of the bolt increases.(3)Based on Johansen’s bolt yield mode,the bearing capacity calculation formulas of bolted joints with slotted-in steel plate in IS,IIIS,IV yield modes are deduced and compared theoretically with the existing test data.The results show that the theoretical calculation results and test results The average error is within 6.21%.(4)The calculation method of the ultimate bearing capacity of the bolted joints with slotted-in steel plate under the combined action of bending moment and shear force is proposed,and the theoretical calculation value is compared with the existing test data.The comparison results show that the experimental values are in good agreement with the theoretical calculation results,verifying that the theoretical calculation has good applicability.(5)The bending moment-rotation curve model of the node during the whole loading process is established and compared with the data in the reference literature.The results show that the theoretical model agrees well with the curve obtained from the test results.(6)A total of 9 bolted joints with slotted-in steel plate with 9 different parameters in3 groups were analyzed.The results show that by increasing the beam section size,bolt diameter and bolt arrangement,the ultimate bearing capacity and elastic stiffness of the joint can be effectively improved.Among them,the effect of increasing the bolt diameter on the mechanical properties of the joint is the most significant.The ultimate bearing capacity of the 20 mm bolt diameter is increased by 48.6%,the elastic rigidity is increased by 35.71%,the ultimate bearing capacity of the 24 mm bolt diameter is increased by 110.6%,and the elastic rigidity is increased by 74.98%.(7)The ABAQUS was used to perform finite element simulation on the two sets of experiments and nine other nodes.The analysis results verified the rationality of the finite element simulation.The bending moment-rotation curve obtained by the finite element simulation is consistent with the overall trend of the theoretically calculated curve.The agreement is good,the deviation is small,affected by the effect of wood cracking simulation,the overall result is slightly larger in the later period.